Snap-action electric switches



D. C. BEER SNAP-ACTION ELECTRIC SWITCHES Filed Sept. 8, 1953 H-llllllllln) .4h-ummm( "mm-mmm nnunum mmnmm fm A ttorn e ys Sept. 30, 1958 ....ub il .vlll

nite States Patent SNAP-ACTION ELECTRICSWITCHES Donald Courtney Beer, Sussex, England Application September 8,*1953, Serial No."37 8,739 12 Claims. (Cl.f200'67) The-present invention'rela'te'sv 'to snapactio'n electric switches of the type comprising a leaf-'springmember resiliently exerting thrust upon a'movableconta'cta'nd arranged to effect closure orA opening of anelectric circuit in a rapid manner when an' operating'fmemberis actuated to cause the thrust-exerting member to snap over its dead-centre position -from one extreme' to the other.

Switches of this general kind are well-known in which the leaf spring is directly'connected to a movable conta'ct that engages one or more fixed contacts inthe body of the switch when the spring snaps' over from one position to the other.

In contradistinction to sucharra'ngements', the presentV invention consists ina switch of this" generalfkind. in which thev movable contact or 'contacts isor "are not directly connected to the thrust-exerting member "but to'a contact-carrying member, itself movedY by'the: 'movement of the 'thrust-exerting `member' in consequence 'upon'actu-- ation by an operating member.-`

According. to one feature of the invention, there is provided a snapaction electric switch comprisingfa rockable contact-carrying member`,"a leaf 1spring' maintained under longitudinal compression with one end engaging or `attached 'to said contactcarrying member' and :the other end engaging or attached to an'actuatingmembe'r 'mova' ble in a direction transverse to the line of' thrust' exerted by'said spring, stops for limiting the extent of'ro'cking of said contact-carrying member, at least one of'saidstops constituting a fixed contact' cooperating'witha'contact carried by the contact-carrying.membenmeans' for moving the actuatingmember throughv a limited distance such that the line of'thrust of thespri'ng 'can be' moved'over.- centre with respect to the rocking axis of the contact*-l carrying member when the latteris in its extremei'limit` ing positions as dened by 'said stops, the'consequent rocking of the contact-carrying member beinglimited by the stops to such a small movement .that the spring will continue to maintain a thrustupon the"contact1carrying'. member after the contact has been'made.`

According to another feature of the'inventionthere is provided a -snap-action electric switch operated by a leaf-spring, comprising an operating member" arranged to'act upon an actuating member thatis adapted 'to'op erate as a movementand-forcemultiplying lever for tensioning a leaf springtov which it is connected at one end, the other end `ofthe spring rocking' a -contac`t' carrying member about a fulcrumV vso thatv when A`the-spring snaps over through an over-centre' position,71 a contact carried bythe said contact-carrying membe'risnaps 'over I from one position to another to make o`1""break an electric Vcircuit'in cooperating with -a xe'd ContactV or con-- tactsassociat'ed with the bodyo'f the switch'.E

Viewed 4from another aspect,the invention provides a snapaction'electric switch iniiwhch aleaf springresilientlyf exerting thrust uponr a fulcrumedLcontact-canryrf ing member is snapped over'zfrom onei extreme lpositlon v tot-another' by an actuatingmembermoved-by adoperata '2,854,536 Patented Sept. 30, 1958 2, ing member exerting pressure on it at one point,.in whichy the mov-able contact' is located 'between the fulcrum point andthe point 'of applied pressure, or 'adjacent the fulcrum point.'

From' yet another aspect', the' invention provides a snap-action electricy switch comprising a leaf lspring arranged to snap a contact-carrying member from one `extreme position to another as a result ofy an.. actuating movement-applied to the spring, the end of the springas soeiat'ed with the contact-carrying member being...fr'ee of restraint so vthat it is free to move in a'direction of vthrust against the `contact-carrying member.

One important advantage accruing from theinvention is that the switch may be constructed 'as a so-called microswitch thatis; a switch in which a comparatively small actuating movement brings about a `high contact pressure.`

In order that* the` invention may be more readily.. understood and appreciated'reference willnow be made to' thetacco'mpanying drawings which show two specific embodiments thereof and in which:

Fig. 1 shows a longitudinal central section through a second embodiment', and

Fig. 2` shows an endview line II-II of Fig.' l.

In the drawingsthere is shown a switch havinga body that fcomprises a block of insulating material 27 which has arela'tively'k deep rectangular recess 28'Aprovided with.' a :substantially rectangular pocket 29 near one end In the 'pocket 29there is provided a'pair 'of loweriixed con tacts 30 having suitableterminal's 31`, the contacts being insulated A each from the other. Each contactlcomprise's astud having an'upper surface of domed'conguration, preferably coate'dfwitli orV made from silver.

Towards the other vend of the block 27 there is provided a metal angle bracket" 32 to' actas a fulcrum for both a metall` 'rocker arm 33 and an actuating member 34 which isalso' Totmetal. The anglel bracket has a base 35"'suit-L ably"apertured at 36 "so that it may-be ixed by means; of a Xing screw and terminal' 37 'into a vblock27, and a side'ange 28.@ The side ilange 38 "is provided'with a dimple or notch`39forming'a fulcrum 'rest'for the rocker arm"'33'r,' the appropriate end ofwhichis radiused at 40 whereby the arm 33` may pivot in a vertical plane in the angle bracket 32.5-I The ange 38 sials'o providedwith an upper aperture' 4I formed 'withfradiused top Land'bottoml faces 42, 43 respectively so that the actuating member 34 may 'pivot therein.

Upper iixed'contacts are provided. at v44"secured to metal plates 45 attached to the 'base of recess'28by screw terminals '46 so that the contacts' 44 Avoverhang the 'pocket 29 and lie respectively above contacts30.

The rocker arm 33 is in the form.l of a vertically-.dise posed web and carries or forms part ofthemoving con' tact 47 of the switch having upper andi-lower .faces48,f 49 respectively adapted to bridge the upper ixed contacts 44 and the lower iixed contacts 30 at its upper and 'lower limits of movement. The upper `iixed contacts 44have a domed-'configuration similar to that of' the'lower con; tacts 30. The:faces'48 and49of contactf47`are prefer! ably -silvered5f and therockerarm 33 fhas= a-notchSO` at its-'forwardr endnformin'gfa locating means for 'one end of .a leaf ys'pring.51,- the opposite'end Tof-"which isaciv commodatedin-ia notch 52 locatedlin'a leg -53 depending from one end ofthe actuating member 34.

In the normal rest position of themembers 33 and"34, shown infull-'lines in-Fig.2, the' :faces 49 of ythe rocker arm' contact memberv47 `bridgesv the' two'.lower'iiixedcori` taets30iand in vthe-:other positionof4 the members shown". dotted-'the upper.- faces 48 fofthe'fcontactiy vmember :47' bridgesethe upperiitedcon'tactsv 46.1

To effect operation of the-rswitchtherelis'providedfa'l partly insection through the composite pressel indicated generally at 54 adapted to be v vertically moved under spring pressure within an extenslon 55 of a cover member 56 tted over the block 27 of insulating material. The pressel-54 ,hasa pressure member 57in the form of a tongue slotted at 58 to engage over an edge 59 of a cut-out portion 60l in the actuating member 34 so that the member 58 and the actuating member 34 always move together. The tongue 58 is secured within a rod of material 61 which is surrounded by a collar 62 adapted to bear, in its lowermost position, on an inwardly-directed ange 63 of a tube 64 which is flanged outwardly at its upper portion at 65. The flange 65 in turn bears on a flange 66 of a further tube 67, the upper portion of which is turned over a frusto-conical portion 68 of an actuating button 69 which is also provided with a retaining flange 70. The button 69 terminates in a cap 71 and a spring 72 is provided between the button 69 and the collar 62 of the pressuremember. A protective collapsible rubber cowl 73 is provided the lower part of which fits over the extension 55 and the upper part of which lits into the space between the cap 71 and the flange 70 as shown.

A plate 74 is fitted in the upper part of the recess 28, the part 74a thereof acting as a stop to limit overtravel of the pressel by limiting the downward movement of ange 63 thereof. Between the plate 74 and the cover member 76 a further rubber protective sheet 75 is provided. The cowl 73 and sheet 75l prevent ingress of moisture or Water to the interior of the switch.

It will be seen that pressure on the button 71 effects downward movement of the member 61 to move the actuating member 34 in a downward direction to ick the moving contact 47 against the upper fixed contacts 44 as shown in dotted lines, under action of spring 53. Upon release of pressure on the button 71, the button 71 returns to its normal upper position and the actuating member 34 returns to its upper or normal position to cause the moving Contact 47 to return to bridge the lower xed contacts 30 as shown in full lines.

Although the pressure member of the accompanying drawings has been shown secured to the operating member 34, it will be understood that, if desired, it may only bear on the upper surface thereof.

It will be seen that, a small movement applied by pressure member 58 of the pressel 54 is multiplied by a second-order lever constituted by the actuating member 34 and to which the leaf spring 51 is attached, so that the actuating movement of the spring, transferred to the rocker arm 33 carrying the moving contact 49, is large compared with the movement of the pressel. The large movement of the spring therefore brings about a high contact pressure for a small actuating movement.

Switches according to the described embodiment of the invention have been satisfactorily manufactured within the following dimensions.

Height overall 2.000 inches. Length overall 2.079i.005 inches. Width overall 0.800 inch.

I claim:

1. A snap-action electric switch comprising at least one fixed contact secured in said switch, a at rigid moving-contact-carrying member, pivot means pivoting said moving-contact-carrying member for movement towards and away from said xed contact and also for rotary movement about said pivot means in a plane transverse to the central plane of said at rigid member, a rigid actuating member, a xed pivot point in said switch for said actuating member, a leaf-spring maintained under longitudinal compression connected between points on said actuating member and said movingcontact-carrying member remote from their said pivots and a pressure member located for pressure upon said actuating member to move said moving-contact-carrying member through said spring.

2. A snap-action electric switch comprising at least one fixed contact secured in said switch, a rigid movingcontact-carrying member comprising a thin web of material having a transversely arranged cross-piece to carry the moving contacts and said web tapering to a rounded end forming the pivot point for said moving-contact-carrying member, a supporting bracket in said switch, a dimple in said supporting bracket, said rounded end of said web locating in said dimple, a rigid actuating member, a fixed pivot point in said switch for said actuating member, a leaf-spring maintained under longitudinal compression connected between points on said actuating member and said moving-contact-carrying member remote from their said pivots, and a pressure member located for pressure upon said actuating member to move said moving-contact-carrying member through said spring, towards and away from said xed contact.

3. A snap-action electric switch comprising two pairs of spaced fixed contacts secured in said switch, a rigid moving-contact-carrying member comprising a thin web of material having a transversely arranged cross-piece to carry the moving contacts and said web tapering to a rounded end forming the pivot point for said moving-contact-carrying member, a supporting bracket in said switch, a dimple in said supporting bracket, said rounded end of said web locating in said dimple, a rigid actuating member, a fixed pivot point in said switch for said actuating member, a leaf-spring maintained under longitudinal compression connected between points on said actuating member and said moving-contact-carrying member remote from their said pivots, and a pressure member located for pressure upon said actuating member to move said moving-contact-carrying member through said spring between said pairs of fixed contacts.

4. A snap-action electric switch comprising at least one xed contact secured in said switch, a flat rigid moving-contact-carrying member carrying contacts on at least one face thereof, means pivoting said moving-contactcarrying member towards and away from said xed contact, a rigid actuating member, a fixed pivot point in said switch for said actuating member, a leaf-spring maintained under longitudinal compression connected between points on said actuating member and said movingcontact-carrying member remote from their said pivots, a pressure member in said switch, a slotted end portion on said pressure member, and a slot in said actuating member, said slotted end of said pressure member locating in said slot in said actuating member.

5. A snap-action electric switch comprising two pairs of spaced xed contacts secured in said switch, a flat rigid moving-contact-carrying member carrying contacts on both opposed faces thereof, means pivoting said moving-contact-carrying member between said pairs of fixed contacts, a rigid actuating member, a fixed pivot point in said switch for said actuating member, a leaf-spring maintained under longitudinal compression connected between points on said actuating member and said moving-contact-carrying member remote from their said pivots, a pressure member in said switch, a slotted end portion on said pressure member, and a slot in said actuating member, said slotted end of said pressure member locating in said slot in said actuating member.

6. A snap-action electric switch comprising at least one fixed contact secured in said switch, a rigid moving-contact-carrying member comprising a thin web of material having a transversely arranged cross-piece to carry the moving contacts and said web tapering to a rounded end forming the pivot point for said movingcontact-carrying member, a supporting bracket in said switch, a dimple in said supporting bracket, said rounded end of said web locating in said dimple, a rigid actuating member, a fixed pivot point in said switch for said arf tuating member, a leaf-spring maintained under 1ongitudinal compression connected between points on said actuating member and said moving-contact-carrying gestage member remote from their said pivots, a pressure member in said switch, a slotted end portion on said pressure member, and a slot in said actuating member, said slotted end of said pressure member locating in said slot in said actuating member.

7. A snap-action electric switch comprising two pairs of spaced fixed contacts secured in said switch, a rigid moving-contact-carrying member comprising a thin web of material having a transversely arranged cross-piece to carry the moving contacts and said web tapering to a rounded end forming the pivot point for said movingcontact-carrying member, a supporting bracket in said switch, a dimple in said supporting bracket, said rounded end of said web locating in said dimple, a rigid actuating member, a xed pivot point in said switch for said actuating member, a leaf-spring maintained under longitudinal compression connected between points on said actuating member and said moving-contact-carrying member remote from their said pivots, a pressure member in said switch, a slotted end portion on said pressure member, and a slot in said actuating member, said slotted end of said pressure member locating in said slot in said actuating member.

8. A snap-action electric switch comprising a switch body, a cover for said body, a moisture-excluding gasket between said cover and said body, at least one xed contact secured in said switch, a at rigid moving-contactcarrying member carrying contacts on at least one face thereof, pivot means pivoting said moving-contact-carrying member for movement towards and away from said fixed contact and also for rotary movement about said pivot means in a plane transverse to the central plane of said member, a rigid actuating member, a fixed pivot point in sa1d switch for said actuating member, a leafspring maintained under longitudinal compression connected between points on said actuating member and said moving-contact-carrying member remote from their said pivots, and a pressure member located for pressure upon said actuating member to move said moving-contactcarrying member through said spring.

9. A snap-action electric switch comprising a switch body, a cover for said body, a moisture-excluding gasket between said cover and said body, two pairs of spaced xed contacts secured in said switch, a liat rigid movingcontact-carrying member carrying contacts on both opposed faces thereof, pivot means pivoting said moving- Icontact-carrying member for movement between said pairs of iixed contacts and also for rotary movement about said pivot means in a plane transverse to the central plane of said member, a rigid actuating member, a ixed pivot point in said switch for said actuating member, a leafspring maintained under longitudinal compression connected between points on said actuating member and said moving-contact-carrying member remote from their said pivots, and a pressure member located for pressure upon said actuating member to move said moving-contactcarrying member through said spring between said pairs of iixed contacts.

10. A snap-action electric switch comprising a switch body, a cover for said body, a moisture-excluding gasket between said cover and said body, two pairs of spaced ixed contacts secured in said switch, a rigid movingcontact-carrying member, means pivoting said movingcontact-carrying member for movement between said pairs of fixed contacts and also for rotary movement about said pivot in a plane transverse 4to the central longitudinal axis of said member, a rigid actuating member, a xed pivot point in said switch for said actuating member, a leaf-spring maintained under longitudinal compression connected between points on said actuating member and said moving-contact-carrying member remote from their said pivots, a pressure member located for pressure upon said actuating member to move said moving-contactcarrying member through said spring between said pairs of fixed contacts, an outwardly extending projection from said cover, said plunger member extending through said projection, and a rubber cowl connected to the outer end of said plunger and to the outer part of said projection.

11. A snap-action electric switch comprising a switch body, a cover for said body, a moisture-excluding gasket between said cover and said body, two pairs of spaced fixed lcontacts secured in said switch, a rigid movingcontact-carrying member comprising a thin web of material having a transversely arranged cross-piece to carry the moving contacts and said web tapering to a rounded end forming the pivot point for said moving-contactcarrying member, a supporting bracket in. said switch, a dimple in said supporting bracket, said rounded end of said web locating in said dimple, a rigid actuating member, a fixed pivot point in said switch for said actuating member, a leaf-spring maintained under longitudinal compression connected between points on said actuating member and said moving-contact-carrying member remote from their said pivots, a pressure member 1ocated for pressure upon said actuating member to move said moving-contact-carrying member through said spring between said pairs of xed contacts, an outwardly extending projection from said cover, said plunger member extending through said projection, and a rubber cowl connected to the outer end of said plunger and to the outer part of said projection.

12. A snap-action electric switch comprising two pairs of spaced iixed contacts secured in said switch, a at rigid moving-contact-carrying member, pivot means pivoting said moving-contact-carrying member for movement between said pairs of xed contacts and also for rotary movement about said pivot means in a plane transverse to the central plane of said flat rigid member, a rigid actuating member, a fixed pivot point in said switch for said ,actuating member, a leaf-spring maintained under longitudinal compression connected between points on said actuating member and said moving-contact-carrying member remote from their said pivots, and a pressure member located for pressure upon said actuating member to move said moving-contact-carrying member through said spring.

References Cited in the tile of this patent UNITED STATES PATENTS 2,125,070 Grooms July 26, 1938 2,157,156 Abendroth May 9, 1939 2,318,734 Baak May 11, 1943 2,355,951 Coieen et al Aug. 15, 1944 2,357,973 Robbins Sept. 12, 1944 2,374,868 Krieger May 1, 1945 2,451,176 Schellman Oct. 12, 1948 2,487,374 Riche et al. Nov. 8, 1949 2,513,804 Kaminky July 4, 1950 2,556,216 Raney June 12, 1951 2,629,791 Le Tourneau Feb. 24, 1953 2,641,663 Krieger June 9, 1953 2,651,692 Slonneger Sept. 8, 1953 2,673,269 Hobbs Mar. 23, 1954 2,681,957 Schneider June 22, 1954 FOREIGN PATENTS 503,504 Great Britain Apr. 6, 1939 

